Current vehicle axles for trucks, buses, trailers and semi-trailers use basically two types of hubs, being either for disc wheels or for wheel rims.
The hubs used with wheel rims are mostly spoke and have different constructive forms, wherein the rim is attached to the ends of the hub spokes by means of clamps secured by bolts. There are also other cases in which a disc hub and a spoke adapter are used.
The hubs used with disc wheels are usually made up of a central body and a flange, wherein the wheels and brake drums are attached to by means of bolts.
The description above may be better understood through patent document P10204591-5.
The wheel hubs for disc wheels of the state of the art have large concentrations of mass in the region where the wheel bolts and brake drums are housed, since their construction shape is that of a flange, as illustrated in FIGS. 5 and 6.
The wheel hubs are also linked to either disc or drum brake systems, wherein part of the heat produced by the brake during braking is transmitted to the hub and to the wheels, especially in freight vehicles where heat generation on the axes is relatively high.
Among the drawbacks found in disc wheel hubs for the vehicle axle of the state of the art, we highlight, as the most relevant, low efficiency in dissipating heat, causing overheating in the hubs, wheels and tires, the most adverse consequence of it being suffered on components with low resistance to temperature, as in the case of tires, grease, bearings and retainers.
Another drawback found in this type of hub is its high weight, requiring over-sizing of the other axle components and vehicle suspension, in addition to resulting in a higher weight of the vehicle itself and, consequently lower cargo.
A solution to overcome part of this problem has been found by reducing the mass of the wheel hub, thereby reducing its weight and manufacturing cost of the product as a whole.
The document U.S. Pat. No. 7,111,911 B2 describes a wheel hub, especially a wheel hub for commercial vehicles, for receiving a brake disk, in which a neck section which is formed on the wheel flange for receiving the brake disk, the neck section being provided with a surface structure, preferably ribs, which increases the amount of the heat given off the environment. There may also be provided ducts between the ribs to permit cooling air to pass between the wheel flange and the brake disk to further increase the amount of heat given off to the environment.
The drawback in the above wheel hub is the fact that it has been designed specifically to be used with a certain type of disc brake, thus not offering a solution for use with drum brake.
The document U.S. Pat. No. 6,866,345 describes a wheel hub comprising a cylindrical main body, a radial flange and a plurality of radial ribs. The main body has an outboard end and an inboard end, and the radial flange has an outboard side and an inboard side. The radial flange is connected to and encircles the main body, with the radial ribs extending between the outboard side of the radial flange and the outboard end of said main body. In addition, the profile of the inboard side of said radial flange is a smooth, continuous curve.
The objective described in this document is to provide a wheel hub with increased resistance to compressive forces, reduced in weight as compared with the traditional wheel hub configuration, and, in addition, provide a sturdy wheel hub that is resistant to deformations in the central orifice of the main body, said deformations being caused by the efforts made by the axle.
The drawback in said invention is that it does not avoid overheating in the wheel hub, since there is no a free area for heat dissipating in the brake (since the flange region is fully closed), compromising prematurely the lifetime of bearings, seals and other components that are low resistant to high temperatures.
There is, therefore, the need to provide a new wheel hub for vehicle axle, said wheel hub being reduced in mass, thereby contributing to reducing the weight and the costs of the suspension components, vehicle and cargo being transported.
This new wheel hub will also improve the heat dissipation caused by the application of the brakes, since there will be a larger free area that will provide improved ventilation.